drivers/mfd/ti_am335x_tscadc.c

   1 /*
   2  * TI Touch Screen / ADC MFD driver
   3  *
   4  * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation version 2.
   9  *
  10  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  11  * kind, whether express or implied; without even the implied warranty
  12  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/err.h>
  19 #include <linux/io.h>
  20 #include <linux/clk.h>
  21 #include <linux/regmap.h>
  22 #include <linux/mfd/core.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/of.h>
  25 #include <linux/of_device.h>
  26 #include <linux/sched.h>
  27
  28 #include <linux/mfd/ti_am335x_tscadc.h>
  29
  30 static unsigned int tscadc_readl(struct ti_tscadc_dev *tsadc, unsigned int reg)
  31 {
  32         unsigned int val;
  33
  34         regmap_read(tsadc->regmap_tscadc, reg, &val);
  35         return val;
  36 }
  37
  38 static void tscadc_writel(struct ti_tscadc_dev *tsadc, unsigned int reg,
  39                                         unsigned int val)
  40 {
  41         regmap_write(tsadc->regmap_tscadc, reg, val);
  42 }
  43
  44 static const struct regmap_config tscadc_regmap_config = {
  45         .name = "ti_tscadc",
  46         .reg_bits = 32,
  47         .reg_stride = 4,
  48         .val_bits = 32,
  49 };
  50
  51 void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tsadc, u32 val)
  52 {
  53         unsigned long flags;
  54
  55         spin_lock_irqsave(&tsadc->reg_lock, flags);
  56         tsadc->reg_se_cache |= val;
  57         if (tsadc->adc_waiting)
  58                 wake_up(&tsadc->reg_se_wait);
  59         else if (!tsadc->adc_in_use)
  60                 tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
  61
  62         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
  63 }
  64 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);
  65
  66 static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
  67 {
  68         DEFINE_WAIT(wait);
  69         u32 reg;
  70
  71         /*
  72          * disable TSC steps so it does not run while the ADC is using it. If
  73          * write 0 while it is running (it just started or was already running)
  74          * then it completes all steps that were enabled and stops then.
  75          */
  76         tscadc_writel(tsadc, REG_SE, 0);
  77         reg = tscadc_readl(tsadc, REG_ADCFSM);
  78         if (reg & SEQ_STATUS) {
  79                 tsadc->adc_waiting = true;
  80                 prepare_to_wait(&tsadc->reg_se_wait, &wait,
  81                                 TASK_UNINTERRUPTIBLE);
  82                 spin_unlock_irq(&tsadc->reg_lock);
  83
  84                 schedule();
  85
  86                 spin_lock_irq(&tsadc->reg_lock);
  87                 finish_wait(&tsadc->reg_se_wait, &wait);
  88
  89                 reg = tscadc_readl(tsadc, REG_ADCFSM);
  90                 WARN_ON(reg & SEQ_STATUS);
  91                 tsadc->adc_waiting = false;
  92         }
  93         tsadc->adc_in_use = true;
  94 }
  95
  96 void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val)
  97 {
  98         spin_lock_irq(&tsadc->reg_lock);
  99         tsadc->reg_se_cache |= val;
 100         am335x_tscadc_need_adc(tsadc);
 101
 102         tscadc_writel(tsadc, REG_SE, val);
 103         spin_unlock_irq(&tsadc->reg_lock);
 104 }
 105 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);
 106
 107 void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tsadc)
 108 {
 109         unsigned long flags;
 110
 111         spin_lock_irqsave(&tsadc->reg_lock, flags);
 112         tsadc->adc_in_use = false;
 113         tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
 114         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
 115 }
 116 EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);
 117
 118 void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val)
 119 {
 120         unsigned long flags;
 121
 122         spin_lock_irqsave(&tsadc->reg_lock, flags);
 123         tsadc->reg_se_cache &= ~val;
 124         tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
 125         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
 126 }
 127 EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
 128
 129 static void tscadc_idle_config(struct ti_tscadc_dev *config)
 130 {
 131         unsigned int idleconfig;
 132
 133         idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
 134                         STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
 135
 136         tscadc_writel(config, REG_IDLECONFIG, idleconfig);
 137 }
 138
 139 static  int ti_tscadc_probe(struct platform_device *pdev)
 140 {
 141         struct ti_tscadc_dev    *tscadc;
 142         struct resource         *res;
 143         struct clk              *clk;
 144         struct device_node      *node = pdev->dev.of_node;
 145         struct mfd_cell         *cell;
 146         struct property         *prop;
 147         const __be32            *cur;
 148         u32                     val;
 149         int                     err, ctrl;
 150         int                     clock_rate;
 151         int                     tsc_wires = 0, adc_channels = 0, total_channels;
 152         int                     readouts = 0;
 153
 154         if (!pdev->dev.of_node) {
 155                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 156                 return -EINVAL;
 157         }
 158
 159         node = of_get_child_by_name(pdev->dev.of_node, "tsc");
 160         of_property_read_u32(node, "ti,wires", &tsc_wires);
 161         of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
 162
 163         node = of_get_child_by_name(pdev->dev.of_node, "adc");
 164         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
 165                 adc_channels++;
 166                 if (val > 7) {
 167                         dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
 168                                         val);
 169                         return -EINVAL;
 170                 }
 171         }
 172         total_channels = tsc_wires + adc_channels;
 173         if (total_channels > 8) {
 174                 dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
 175                 return -EINVAL;
 176         }
 177         if (total_channels == 0) {
 178                 dev_err(&pdev->dev, "Need atleast one channel.\n");
 179                 return -EINVAL;
 180         }
 181
 182         if (readouts * 2 + 2 + adc_channels > 16) {
 183                 dev_err(&pdev->dev, "Too many step configurations requested\n");
 184                 return -EINVAL;
 185         }
 186
 187         /* Allocate memory for device */
 188         tscadc = devm_kzalloc(&pdev->dev,
 189                         sizeof(struct ti_tscadc_dev), GFP_KERNEL);
 190         if (!tscadc) {
 191                 dev_err(&pdev->dev, "failed to allocate memory.\n");
 192                 return -ENOMEM;
 193         }
 194         tscadc->dev = &pdev->dev;
 195
 196         err = platform_get_irq(pdev, 0);
 197         if (err < 0) {
 198                 dev_err(&pdev->dev, "no irq ID is specified.\n");
 199                 goto ret;
 200         } else
 201                 tscadc->irq = err;
 202
 203         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 204         tscadc->tscadc_base = devm_ioremap_resource(&pdev->dev, res);
 205         if (IS_ERR(tscadc->tscadc_base))
 206                 return PTR_ERR(tscadc->tscadc_base);
 207
 208         tscadc->regmap_tscadc = devm_regmap_init_mmio(&pdev->dev,
 209                         tscadc->tscadc_base, &tscadc_regmap_config);
 210         if (IS_ERR(tscadc->regmap_tscadc)) {
 211                 dev_err(&pdev->dev, "regmap init failed\n");
 212                 err = PTR_ERR(tscadc->regmap_tscadc);
 213                 goto ret;
 214         }
 215
 216         spin_lock_init(&tscadc->reg_lock);
 217         init_waitqueue_head(&tscadc->reg_se_wait);
 218
 219         pm_runtime_enable(&pdev->dev);
 220         pm_runtime_get_sync(&pdev->dev);
 221
 222         /*
 223          * The TSC_ADC_Subsystem has 2 clock domains
 224          * OCP_CLK and ADC_CLK.
 225          * The ADC clock is expected to run at target of 3MHz,
 226          * and expected to capture 12-bit data at a rate of 200 KSPS.
 227          * The TSC_ADC_SS controller design assumes the OCP clock is
 228          * at least 6x faster than the ADC clock.
 229          */
 230         clk = clk_get(&pdev->dev, "adc_tsc_fck");
 231         if (IS_ERR(clk)) {
 232                 dev_err(&pdev->dev, "failed to get TSC fck\n");
 233                 err = PTR_ERR(clk);
 234                 goto err_disable_clk;
 235         }
 236         clock_rate = clk_get_rate(clk);
 237         clk_put(clk);
 238         tscadc->clk_div = clock_rate / ADC_CLK;
 239
 240         /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
 241         tscadc->clk_div--;
 242         tscadc_writel(tscadc, REG_CLKDIV, tscadc->clk_div);
 243
 244         /* Set the control register bits */
 245         ctrl = CNTRLREG_STEPCONFIGWRT |
 246                         CNTRLREG_STEPID;
 247         if (tsc_wires > 0)
 248                 ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 249         tscadc_writel(tscadc, REG_CTRL, ctrl);
 250
 251         /* Set register bits for Idle Config Mode */
 252         if (tsc_wires > 0)
 253                 tscadc_idle_config(tscadc);
 254
 255         /* Enable the TSC module enable bit */
 256         ctrl = tscadc_readl(tscadc, REG_CTRL);
 257         ctrl |= CNTRLREG_TSCSSENB;
 258         tscadc_writel(tscadc, REG_CTRL, ctrl);
 259
 260         tscadc->used_cells = 0;
 261         tscadc->tsc_cell = -1;
 262         tscadc->adc_cell = -1;
 263
 264         /* TSC Cell */
 265         if (tsc_wires > 0) {
 266                 tscadc->tsc_cell = tscadc->used_cells;
 267                 cell = &tscadc->cells[tscadc->used_cells++];
 268                 cell->name = "TI-am335x-tsc";
 269                 cell->of_compatible = "ti,am3359-tsc";
 270                 cell->platform_data = &tscadc;
 271                 cell->pdata_size = sizeof(tscadc);
 272         }
 273
 274         /* ADC Cell */
 275         if (adc_channels > 0) {
 276                 tscadc->adc_cell = tscadc->used_cells;
 277                 cell = &tscadc->cells[tscadc->used_cells++];
 278                 cell->name = "TI-am335x-adc";
 279                 cell->of_compatible = "ti,am3359-adc";
 280                 cell->platform_data = &tscadc;
 281                 cell->pdata_size = sizeof(tscadc);
 282         }
 283
 284         err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
 285                         tscadc->used_cells, NULL, 0, NULL);
 286         if (err < 0)
 287                 goto err_disable_clk;
 288
 289         device_init_wakeup(&pdev->dev, true);
 290         platform_set_drvdata(pdev, tscadc);
 291         return 0;
 292
 293 err_disable_clk:
 294         pm_runtime_put_sync(&pdev->dev);
 295         pm_runtime_disable(&pdev->dev);
 296 ret:
 297         return err;
 298 }
 299
 300 static int ti_tscadc_remove(struct platform_device *pdev)
 301 {
 302         struct ti_tscadc_dev    *tscadc = platform_get_drvdata(pdev);
 303
 304         tscadc_writel(tscadc, REG_SE, 0x00);
 305
 306         pm_runtime_put_sync(&pdev->dev);
 307         pm_runtime_disable(&pdev->dev);
 308
 309         mfd_remove_devices(tscadc->dev);
 310
 311         return 0;
 312 }
 313
 314 #ifdef CONFIG_PM
 315 static int tscadc_suspend(struct device *dev)
 316 {
 317         struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 318
 319         tscadc_writel(tscadc_dev, REG_SE, 0x00);
 320         pm_runtime_put_sync(dev);
 321
 322         return 0;
 323 }
 324
 325 static int tscadc_resume(struct device *dev)
 326 {
 327         struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 328         unsigned int restore, ctrl;
 329
 330         pm_runtime_get_sync(dev);
 331
 332         /* context restore */
 333         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 334         if (tscadc_dev->tsc_cell != -1)
 335                 ctrl |= CNTRLREG_TSCENB | CNTRLREG_4WIRE;
 336         tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
 337
 338         if (tscadc_dev->tsc_cell != -1)
 339                 tscadc_idle_config(tscadc_dev);
 340         restore = tscadc_readl(tscadc_dev, REG_CTRL);
 341         tscadc_writel(tscadc_dev, REG_CTRL,
 342                         (restore | CNTRLREG_TSCSSENB));
 343
 344         tscadc_writel(tscadc_dev, REG_CLKDIV, tscadc_dev->clk_div);
 345
 346         return 0;
 347 }
 348
 349 static const struct dev_pm_ops tscadc_pm_ops = {
 350         .suspend = tscadc_suspend,
 351         .resume = tscadc_resume,
 352 };
 353 #define TSCADC_PM_OPS (&tscadc_pm_ops)
 354 #else
 355 #define TSCADC_PM_OPS NULL
 356 #endif
 357
 358 static const struct of_device_id ti_tscadc_dt_ids[] = {
 359         { .compatible = "ti,am3359-tscadc", },
 360         { }
 361 };
 362 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
 363
 364 static struct platform_driver ti_tscadc_driver = {
 365         .driver = {
 366                 .name   = "ti_am3359-tscadc",
 367                 .owner  = THIS_MODULE,
 368                 .pm     = TSCADC_PM_OPS,
 369                 .of_match_table = ti_tscadc_dt_ids,
 370         },
 371         .probe  = ti_tscadc_probe,
 372         .remove = ti_tscadc_remove,
 373
 374 };
 375
 376 module_platform_driver(ti_tscadc_driver);
 377
 378 MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 379 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 380 MODULE_LICENSE("GPL");